Qst, the link you provided was about making nitric.
I found this post by Goldsilverpro: "I think I read on the web that ammonium nitrate detonates when heated to 800 deg F. That's not normally going to happen but, that's not where the danger is.
Let's say you made A.R. from ammonium nitrate. Now you have ammonium ion in the solution.
You dissolve the gold and drop it out. Now you have heavy metals and ammonium ion in the solution.
Next you do what every good refiner does. You neutralize the acid solution with lye - sodium hydroxide
Now you have all of the requirements for a disaster - ammonia, metal, and sodium hydroxide. Also, the solution is now a little alkaline - another requirement."